Cooling slide

ABSTRACT

A vinyl sheet material is formed on consolidation rolls. As the vinyl sheet material leaves the rolls, it is placed upon an inclined water slide. At the end of the water slide there is positioned a pair of pinch rolls which retard the movement of the vinyl sheet down the water slide. The vinyl sheet is actually pushed down the water slide and thereby develops compressive stresses therein. The vinyl sheet is later cut into individual tile units.

United States Patent Young Jan. 14, 1975 1 COOLING SLIDE 2,722,265 111955 Kelly ct al .1 264/245 X 3,276,076 10/1966 Ryan et a1 425/71 [75]Inventor- Ymmg, Lancaster 3,518,722 7/1970 Ryan et a1 425 71 [73]Assigneez Armstrong Cork company 3,635,614 1/1972 Long et al 425/71Lancaster, Pa.

- Primary Examiner-Andrew R. Juhasz [22] Flled' June 1973 AssistantExaminerR. J. Craig [21] Appl. No: 366,466

Related US. Application Data 57 ABSTRACT 62 D' fS .N 243,271, A'll2,1972. M510 0 er 0 pm A vinyl sheet matenal 1s formed onconsol1dat1on rolls. [52] Cl 425/308 264/180 425/404 As the vinyl sheetmaterial leaves the rolls, it is placed I 425/445 425/363 upon aninclined water slide. At the end of the water [51] Int. Cl. 1329c 17/14Slide there is psitined Pair of Pinch 0118 which [58] Field of Search264/153 180 425/71 tard the movement of the vinyl sheet down the water425/308 11:04 slide. The vinyl sheet is actually pushed down the waterslide and thereby develops compressive stresses [56] References Citedtherein. The vinyl sheet is later cut into individual tile UNITED STATESPATENTS i 2,338,770 1/1944 Leguillon 425/71 X 2 Claims, 1 Drawing FigureCOOLING sums CROSS-REFERENCE TO RELATED APPLICATION This is a divisionof application Ser. No. 243,271, filed Apr. 12, 1972.

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention isdirected to an apparatus and method for making a sheet material and,more particularly, to a sheet material which is made into floor tile.

2. Description of the Prior Art It is old in the flooring art to makefloor tile by forming a sheet material on a mill which is a pair ofconsolidation rolls. The vinyl sheet material is stripped off the rollsand cooled by passing the sheet material through a water bath. The sheetmaterial then, after cooling, is passed down to a conventional punchpress structure which stamps individual 12 inch X 12 inch tiles from thesheet material. Tile normally formed in this manner is formed withtension stresses therein. That is, during the cooling of the vinylsheet, it was subject to tension along the direction of sheet travel.When the vinyl sheet is cooled, the stresses in the sheet due to thetension on the sheet are set in the sheet. When the sheet is cut intosmall individual tile units, the mass of the sheet is not sufficient toprevent the sheet from shrinking in the along-machine-direction as thestresses relax. The only way the tension stresses are relaxed in thesheet is for the sheet to shrink in its along-machinedirection ofprocessing. This results in a tile which is unstable and when thesetiles are placed on a flooring, the changing of the size of the tilescauses the development of gaps between individual tiles.

US. Pat. No. 2,973,770 discloses that it is old to use a water slide forsliding a piece of material down into a water bath. Therein the gravityaction on the piece of material is permitted to carry it down the waterslide and then into the water bath. The material is then pulled out ofthe water bath in a cool state. Herein there is no particularconsideration to stresses and the fact that the material is moving bygravity down an inclined surface means that the material is being pulledoff the forming structure due to the mass of the material which isalready on the water slide. This creates tension stresses within thematerial, which stresses are locked into the material as it is cooled.

SUMMARY OF THE INVENTION Tile units are cut from a sheet. The sheet isinitially formed on consolidating rolls which take a mass of vinylmaterial, in a sticky granular form, and convert the vinyl material to asheet. The sheet is fed off of one of the rolls onto an inclined slidewhich has water flowing therealong. At the end of the slide, a set ofpinch rolls retards the movement of the vinyl sheet down the waterslide. The pinch rolls are rotating at a speed less than that of theconsolidating rolls. This results in the setting of a subtle compressionwithin the sheet during the cooling process. The sheet can be laid assheet flooring or installed as a wall covering or the sheet may bepassed to a punch press structure to have individual tile units formed.The above-described technique has been found to be particularly usefulin the forming of tile from an all-vinyl material. However, it can beused also with vinyl material which has been filled with asbestos, whichprovides a hot strength to the vinyl sheet.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic view of theinvention herein.

DESCRIPTION OF THE PREFERRED EMBODIMENT The tile may be formed from thematerial such as that set forth in US. Pat. No. 2,773,851. The productis made basically in the same manner as that set forth for making theproducts of the above-mentioned patent. The invention herein is in themeans used to cool the blanket of the above-mentioned patent. Theinvention herein could be equally well used with that of commonlyassigned application Ser. No. 866,71 I, filed Oct. 15, 1969, in the nameof George W. Loosemore and entitled Organic Fiber-Filled Tile nowabandoned. The process can be used particularly to make a vinyllimestoneproduct which has no fiber fillers. Also the process is not limited tovinyl compositions, but may be used with thermoplastic binder systems ingeneral, and particularly to systems using asphalt, coumaroneindene,polystyrene, polyurethane, etc.

Referring to the drawing, it will be seen that the mill or rollstructure which forms the vinyl sheet material is composed of two rolls,the upper roll 1 and the lower roll 2. The product could be made on afirst mill which is then followed by a calender roll structure toprovide the sheet material with a smooth surface. The product canequally well be made in the manner shown in which the mill and calenderare combined as a single structure, the consolidating rolls. If a smoothsurface product is to be formed, the upper roll 1 will be of polishedsteel. When a smooth surface product is formed, the formed sheetmaterial 3 tends to stick to the upper roll for a short time after itpasses through the nip of the rolls. A conventional doctor blade removesthe sheet material from the upper roll when it is formed with a smoothsurface. When the upper roll 1 is provided with an embossed pattern, thelower roll 2 then usually has a hard rubber surface, and the sheetmaterial or blanket 3 then has an affinity to stick to the lower rollsurface. A doctor blade then is used to strip the blanket off the lowerroll 2, and a guide structure 4 is used to direct the blanket up ontothe water slide.

The water slide will consist of a series of sections, each section willfunction as a separate zone in the slide. The composite slide will, inessence, appear to be a flat stainless steel plate with holes drilledthrough the surface. The purpose of the holes is to allow water or airto well-up through the surface of the plate. The water will supply afluid media to convey and cool the tile blanket as it moves down theslide 5. The surface 6 of the conveyor will have the fluid medium layerwhich is used to cool and convey the tile blanket. The size and numberof holes required will be a function of the water capacity, the jetvelocity needed for uniform cooling, the convection cooling dwell timefor water, and the head requirements needed to support the weight of thetile blanket. Between each zone there will be a return water trough toremove the warmed water. The conveyor will be pivotally mounted at point7 so that the elevation of the infeed end of the conveyor can be changedto pick the blanket off either the top or bottom roll. Any change in theelevation can be accomplished by any normal type of lifting structures,for example, air cylinders.

So-called air doctors 8 may be utilized both above and below the blanketto blow excess water off the blanket as it comes off the conveyor 5. Atthe time the blanket leaves the conveyor, it will have been cooled tosuch a point that it is now sufficiently rigid to be handled. At the endof the conveyor is a pinch roll feeder structure composed of an upperroll 9 and a lower roll 10. The speed of the pinch roll feeder will bemechanically related to the speed of rolls 1 and 2. The bottom roll 10may be knurled steel while the top roll 9 will probably be arubber-coated roll. The rolls will be approximately 6 inches indiameter. The nip pressure will be regulated by two air cylinders whichwill operate to maintain a nip pressure of approximately 2 pounds perlinear inch of material passing through the nip of the two rolls. Theretarding effect of the pinch rolls can be accomplished by the use of aslow-moving conveyor which is positioned at the end of the water slide.The mass of the sheet material on the slow conveyor will still maintainthe compression in the blanket 3.

In principle, the tile blanket will be pushed onto the water slide. Toaccomplish this, a hump 11 in the tile blanket 3 will be maintained onthe infeed end of the water slide. This hump 11 must be maintained atall times, and it can be maintained by an operator visually watching itor a simple photoelectric cell control system could be provided fordetecting and regulating the hump. The amount of the hump 11 in theblanket will be regulated by the ratio of the speed of the consolidatingrolls (1 and 2) versus the speed of the pinch rolls (9 and 10). Due tothermal shrinkage, the blanket velocity out of the water slide will beabout 0.994 of the velocity in. The velocity into the water slide willbe the top roll surface speed for smooth surface patterns, and thebottom roll surface speed for embossed patterns. It is obvious from theabove that the speed of rotation of the rolls 9 and 10 will be somewhatless than the speed of rotation of the rolls 1 and 2. This lesser speedwill be due to the fact that there will be shrinkage of the blanket onthe water slide, and this lesser speed is needed for the maintaining ofthe hump 11. With the pinch rolls or any other retarding assembly ineffect holding back on the movement of the blanket down the water slideand the pushing of the blanket down the water slide by the rolls 1 and2, as evidenced by the presence of the hump 11, it will be seen that theslide is constructed in such a way as to keep the blanket in subtlecompression during the cooling process. This approach eliminates thestresses which were previously caused in old systems by the thermalcontraction and mechanical stretching. In effect, the blanket is beingcooled from 350 F. to about 100 F. with compression stresses rather thantension stresses. When the tile blanket is later cut into tiles, by apress structure 12, as is conventional in the art, and the tiles arelaid on a floor, there will not be the development of gaps betweenindividual tiles as stresses relax. If the tile has been laid on a floorfor a period of time, the stresses in the tile will gradually relax. lfthere are tension stresses in the tile, the relaxing of these stresseswill cause a reduction in the length of the tile in the machinedirection in which the tile was made. This results in the development ofa gap between pieces of tile. If the tile is made with a compressionstress therein, as the stresses relax, there would be a tendency for thetile to grow in size. However, since the tile is now laid within a floorpattern, it is not possible for the tile to grow because there areadjacent tiles holding it in place. A side advantage of the use of thewater slide is that shrinkage across the machine direction is alsoreadily permitted.

What is claimed is:

1. An apparatus for forming a product consisting of consolidating rollmeans which is used to convert bulk thermoplastic material into sheetform and push the formed sheet in an initial processing direction,including in the sheet processing direction beyond the consolidatingroll means an inclined slide structure means with a top surface and aninlet and outlet end, said slide having a fluid medium flowing down thetop surface of the slide, said formed sheet moving down the slide on thefluid medium from the inlet end to the outlet end of the slide, means atthe outlet end of the slide for retarding movement of the sheet down theslide, said retarding means positively grasping and conveying the sheetfrom the slide at a speed less than the speed the sheet is fed onto theslide by the consolidating roll means, said speed difference beinggreater than that which would occur from just simple sheet sizeshrinkage such that the sheet is formed with a free-standing humptherein at the inlet end of the slide, said retarding means functionswith the consolidating roll means and their speed difference to operateas a means to form beyond the retarding means an end product withcompressive stresses therein and means provided for cutting the sheetinto compressed state individual tile units.

2. The apparatus of claim 1 wherein said consolidating roll meanscomprises a top consolidating roll and a bottom consolidating roll andthe slide is pivotally mounted at its outlet end so that the inlet endof the slide can be positioned to take a sheet stripped off either thetop consolidating roll or the bottom consolidating roll.

1. An apparatus for forming a product consisting of consolidating rollmeans which is used to convert bulk thermoplastic material into sheetform and push the formed sheet in an initial processing direction,including in The sheet processing direction beyond the consolidatingroll means an inclined slide structure means with a top surface and aninlet and outlet end, said slide having a fluid medium flowing down thetop surface of the slide, said formed sheet moving down the slide on thefluid medium from the inlet end to the outlet end of the slide, means atthe outlet end of the slide for retarding movement of the sheet down theslide, said retarding means positively grasping and conveying the sheetfrom the slide at a speed less than the speed the sheet is fed onto theslide by the consolidating roll means, said speed difference beinggreater than that which would occur from just simple sheet sizeshrinkage such that the sheet is formed with a free-standing humptherein at the inlet end of the slide, said retarding means functionswith the consolidating roll means and their speed difference to operateas a means to form beyond the retarding means an end product withcompressive stresses therein and means provided for cutting the sheetinto compressed state individual tile units.
 2. The apparatus of claim 1wherein said consolidating roll means comprises a top consolidating rolland a bottom consolidating roll and the slide is pivotally mounted atits outlet end so that the inlet end of the slide can be positioned totake a sheet stripped off either the top consolidating roll or thebottom consolidating roll.